Blowpipe tip



March 6, 1934. CAMPBELL,v JR 1,949,780

BLOWPIPE TIP Filed Feb. 13. 1931 lll /fwfw Patented Mar. 6, 1934 UNITEDSTATES PATENT OFFICE 2 Claims.

This invention relates to the production of a tip for cutting blowpipescomprising inner and outer tip members, wherein the inner member isprovided with a central bore for cutting oxygen extending therethroughand with a series of longitudinally extending slots which, when theouter member is applied to the inner member, are converted into passagesfor the preheating mixture of combustible gas and oxygen. Specifically,the inner tip member is provided in the tapered operating end thereofwith a series of slots, the body of said tip member being annularlyrecessed between the series of slots whereby, on assembling the outertip member upon the inner tip member, a series of upper channels forpreheating mixture will be formed, the lower ends of these channelsdelivering the mixture into an annular chamber whence the preheatingmixture is delivered through the lower series of passages to theoperating end of the tip. In practice, the channels in each series havebeen equidistantly spaced.

For the purpose of assembling the inner and the outer members, it hasbeen proposed to unite the same by inserting a key into the upper end ofone of the upper passages, formed by assembling the outer tip memberupon the inner tip member, thus converting this passage into a keyway,the outer surface of the key gripping the inner surface of the outermember. This results in blocking oif one of the passages, with acorresponding restriction in the volume of the preheating mixture thatmay be supplied to the operating end of the tip and also with a more orless unequal distribution of the preheating mixture supplied from suchupper passages to the lower series of passages extending to theoperating end of the tip. The equidistant spacing of the upper slots isnecessary on account of the design of the tip, the inner tip member notbeing sufciently large to provide room between adjacent slots for aspecial keyway for the insertion of a key. Furthermore, the size of thetip is so restricted that it cannot be enlarged to widen the spacebetween adjacent slots sufliciently to accommodate a keyway.

Further objections to the former mode of connecting the inner and outertip member are; the expense of making the keys; the necessity for re-'moving burrs therefrom so that the outer tip member may slide over thekey which has been inserted into the slot selected therefor; and alsothe necessity for inserting the key in exactly the right position insuch slot in the inner tip member.

It is the general purpose and object of my in- (Cl. 15S-27.4)

vention to so construct and connect inner and outer tip members of thecharacter heretofore referred to as to enable all of the passages in theupper portion of the tip to conduct the preheating mixture; to eliminatethe necessity for making and inserting keys; and generally to increasethe capacity and efciency of tips of this character.

I secure the foregoing advantages by constructing the inner tip memberand assembling the inner and outer tip members in the manner shown inthe drawing hereof, wherein Fig. 1 represents a central verticalsectional view through the head of a blowpipe having a tip embodying myinvention; Fig. 2 a side elevation of the inner tip member of suchblowpipe; Fig. 3 a detail in section corresponding to the line 3-3 ofFig. 1; and Fig. 4 a detail in section corresponding to the line 4 4 ofFig. 2.

Describing by reference characters the various parts illustrated, 1denotes the head of a blowpipe to which my tip is attached, the saidhead being provided with a neck 2 having in the upper portion thereof abranched passageway 3 communicating at its forward end with a chamber 4,the head also having upwardly inclined passageways 5 and 6.Communicating with the rear or receiving ends of the passageways 3, 5and 6 are the pipes '7, 8 and 9 which serve to conduct cutting oxygen,preheating oxygen, and combustible gas, respectively, to the saidpassageways. Thefupper end of the passageway 5 is shown as communicatingwith a chamber 10 formed by a bore extending downwardly and forwardlyinto said head and having threaded thereinto the body 1l of an injector,the said injector having a stem 12 extending through said chamber andbeing provided with an operating head 13, between which and a seat 14 onsaid head a packing ring l5 is inserted. The injector is provided with acentral bore 16, the upper end of which communicates by lateral ports 17with the chamber l0 and the lower end of which bore is adapted todischarge centrally into an inclined passageway 18 which in turndischarges into an annular chamber 19 provided in the lower portion ofthe blowpipe head above the outer tip member and surrounding the upperportion of the inner tip member. The passageway 6 discharges into achamber 20 surrounding the lower end of the injector and communicatingwith the passageway 18.

Extending downwardly from the chamber 4 is a short passageway 2l whichmerges with an enlarged threaded bore 22 extending to the charnber 19.

The blowpipe head just described is one which is adapted to cooperatewith a tip construction, which will now be described. 23 denotesgenerally an inner tip member having a cylindrical main body portion 24,with an upper threaded extension 25 adapted to engage the thread of thebore 22, the upper end of the tip member being reduced and having aconvex seating portion 26 adapted to engage a beveled seat 27 below thelower end of the passage 21. Below the body portion 24, the inner tipmember is provided with a downwardly tapered reduced portion 28, therebeing an annular shoulder 24@l provided between the top of such reducedportion and the-body portion 24, the lower end of the tip member beingfrusto-conical, as shown at 29, and there being an outwardly extendingshoulder 30 between the upper `end of such frusto-conical portion andthe reduced portion 28. f

The inner tip member is provided with a central bore 31 the upper end ofwhich receives cutting oxygen from the chamber 4 and the passage 21, thelower end of the bore being reduced, -as shown at 31a. The body portion24 is provided with a plurality of equidistantly spaced slots 32extending radially inwardly from the outer surface thereof, the upperends of the slots being spaced from the threaded portion 25. Five suchslots are shown and, while the number of the slots may be varied, thisnumber provides, when the outer tip member is assembled upon the innertip member, passages of suflicient aggregate cross sectional area. toinsure an eicient preheating operation without unnecessarily weakeningthe walls of ythe dovetailed ribs 33 which separate the said passages.The slots 32 extend through and below the shoulder 24, and the lowerfrustoconical end of the inner tip member is provided with a pluralityof equidistantly spaced slots 34 extending the full length of suchfrusta-conical portion and, when converted into passages by mounting theouter member thereon, serving to deliver to the operating end of the tipa convergent series of jets of preheating gas.

Cooperating with the inner tip member 23 is an outer tip member,indicated generally at 35, the outer member having a cylindrical upperportion 36 adapted to fit snugly about the cylindrical body 24 of theinner member, thereby sealing the slots 32 and providing passages forthe preheating mixture. The top of the inner tip member terminates belowthe upper ends of the slots 32 whereby the slots communicate with theannular chamber 19 provided in the head when the tip is assembledtherein, as indicated in Fig. 1. The lower end of the outer tip memberis frusto-conical, as shown at 37, and ts snugly about thefrusto-conical lower end of the inner tip member, thereby sealing theouter ends of the slots 34 to form passages for the preheating mixturewhich is delivered through the upper passages into the annular chamber38 provi-ded between the inner wall of the outer tip member and thereduced portion 28 of the inner tip member.

For the purpose of uniting the inner and outer tip members, I subject aportion of one of the ribs to a pressing action, exerted on oppositesides of the rib, whereby a key 39 is provided. the sai-d key projectingradially beyond the body of the rib and being substantially rectangularin section and narrower than the remaining portion of the rib. Becauseof the fact that this key projects radially outwardly beyond the rib 33,the outer member is provided with a slot 40 constituting a keyway andextending downwardly from the upper end of the outer member a distancesulhcient to accommodate the key during the operation of pressing theouter member upon the inner member.

By constructing and assembling the tip members in the manner described,I am enabled to obtain an extra passage for the preheating mixture inthe upper portion of the tip. This, for the same size of tip, enables meto increase by 20% the aggregate cross sectional areas of the passagesfor gas, which results in a correspond- -ing decrease in the velocity ofthe gas supplied through such passages. These passages conduct the gasin contact with the heated shell of the outerl tip member, thus not onlyexpanding the gas, but raising the temperature thereof so as to securebetter combustion of the preheating mixture. `It is important to have asmuch heated area as possible for the mixture flowing through thepassages 32 and to deliver the mixture through such passage at as slowvelocity as possible. This result is secured by the manner ofconstructing and assembling the inner and outer tip members. v

Furthermore, because of the fact that theinner tip member is made ofductile material, such as bronze, when a `portion of one of the ribs 33is subjected to pressure to form the key 39, this results in compactingthe molecular structure -of such key and increasing the density thereof,whereby it is enabled the better to perform its function.

It will be noted that the lower end of the inner tip member is shown asterminating above the lower end of the outer tip member, whereby achamber 41 is provided below the lower end of the inner tip member. Thischamber is parits lio

ticularly useful in enabling the blowpipe to be operated without dangerof blowing out the flame through the pressure of the oxygen deliveredthrough the bore 312.

Having thus described my invention, what I claim is:

1. A blowpipe tip comprising in combination an outer member having acylindrical upper body portion and a lower frusto-conical end portion,an inner member having its upper end projecting beyond the upper end ofthe outer member and provided with means for attachment to a blowpipehead and also provided with a central bore for cutting oxygen and havingan upper cylindrical portion adapted to be received within thecylindrical portion of the outer member and a lower downwardly taperedreduced end portion adapted to be received within the frustoconicalportion of the outer tip member, the cylindrical portion of the innermember fitting closely within the cylindrical portion of the outermember and extending substantially the full length of the cylindricalportion of said outer member, the cylindrical portion of the innermember being provided with slots extending inwardly from the exteriorthereof and forming passages for a preheating mixture with the outermember, the upper ends of the slots extending as far as the upper end ofthe outer member and the lower ends of the said slots extending tosubstantially the lower end of the cylindrical portion of the outermember, the slots being spaced equidistantly and being separated byribs, one of said ribs having an integral longitudinal key extendingradially beyond the outer surfaces of the other ribs, the outer memberbeing provided with a keyway receiving the said key, the said i... fi)

tip having passages at the delivery end thereof for preheating mixturesupplied through the first mentioned passages.

2. A blowpipe tip comprising in combination an outer member having acylindrical upper body portion and a lower frusto-conical end portion,an inner member having its upper end projecting beyond the upper end ofthe outer member and provided with means for attachment to a blowpipehead and also provided with a central bore for cutting oxygen and havingan upper cylindrical portion adapted to be received within thecylindrical portion of the outer member and a lower downwardly taperedreduced end portion adapted to be received within the frusto-conicalportion of the outer tip member, the cylindrical portion of the innermember fitting closely within the cylindrical portion of the outermember and extending substantially the full length of the cylindricalportion of said outer member, the

cylindrical portion of the inner member being provided with slotsextending inwardly from the exterior thereof and forming passages for apreheating mixture with the outer member, the upper ends of the slotsextending as far as the upper end of the outer member and the lower endsof the said slots extending to substantially the lower end of thecylindrical portion of the outer member, the slots being spacedequidistantly and being separated by ribs, one of said ribs having anintegral longitudinal key extending radially beyond the outer surfacesof the other ribs and being of less width than the width of the outersurface from which it extends, the outer member being provided with akeyway receiving the said key, the said tip having passages at thedelivery end thereof for preheating mixture supplied through the rstmentioned passages.

LORN CANIPBELL, JR.

